should I upgrade to macOS Catalina?

as always, a big NO!

1. are you using Adobe apps? Do NOT even attempt to try Catalina – serious issues with those apps, and Adobe is late releasing the updates.

Not to mention, some components of Adobe apps are 32 bit, and you will not be able to use the Uninstallers to clean old Adobe apps

2. you have to check if all your apps are 64 bit – old 32 bit apps will no longer work.

Go here to see: Apple / About This Mac / System Report… then on the left side go to Software / Legacy Software…

3. read this old cogitation on this topic that is still a golden rule:

3. data loss in Apple Mail of Catalina

https://www.macrumors.com/2019/10/12/apple-mail-data-loss-macos-catalina/